That folder never gets cleared.

From what I know applications are meant to clean up after themselves.

But rarely, applications do this. The only notable exceptions is Winrar temp-extractions and some installers. Most other products simply let their stuff rot in TEMP hell.

Actually there are two TEMPs, one Local Settings and one Roaming Settings TEMP. But unlike most linuxes, Windows doesn't clean them, and some applications even fuck up when you delete their temp-stuff.

You mean %TEMP%.